One of my favorite writing resources is Techniques of the Selling Writer by Dwight Swain. Last night in our jabber chat meeting, AmaranthMuse asked for help on how to get rid of the long, boring stretches in between the action scenes. Conveniently, Dwight writes about just this problem. See this online summary about how to write sequels, the "transition period that links two scenes." (this online summary is from this nice collection of Dwight Swain articles).
There is a page on our wiki that lists recommendations for books on writing. Feel free to add to the list.
What writing books do you like and recommend? And what are some key lessons you've learned from these books?